I've been fooling around with the new Resize Pro Plugin from Fred Miranda. It does what its name implies: it resizes your photos.
Big whoopee, you say? That's a feature of every image editor on the planet? Well, yes and no.
If
you don't care much about the results when resizing your photos, then
maybe that's true. But the issue of how to upsample (make your photo
larger in order to print, for example) or downsample (make it smaller in
order to put it on the Web, say) bitmapped files is so important that
Photoshop introduced two new resizing methods in Photoshop CS: Bicubic
Sharper and Bicubic Smoother. Bicubic Sharper is intended for
downsampling and Bicubic Smoother for upsampling.
But there are even better methods than those in Photoshop CS. For upsampling, I have relied on the Pyramid method in the recent versions of Qimage. I've
been happy so far with the results. For downsampling for the Web, I use
Bicubic Sharper, but I step down with multiple
incremental reductions to 66% until I get close to the size I need
and then do a final adjustment to get my final size. I first heard of
this idea from Jeff Schewe.
For
example, photos from my Canon 20D are 3520x2346 pixels. I like to put
them on the Web at 800x533. I have an action that resizes to 66% of
the previous image size 3 times using Bicubic Sharper, and then does a
final resize to 800x533. After the first step, the 3520–pixel maximum
dimension is 2323 pixels. It's then 1533 pixels after the second 66%
resize. The third pass takes it to 1011 pixels. A fourth pass would
reduce it to 667 pixels: too small. So after the third pass the action
explicitly sets the width to 800 pixels.
The 20D Resize Pro is
very good at downsampling. It's no better than the technique I use,
but it's not worse, either, and it's the first method I've found that
equals it. Very well done, Fred.
But the real purpose of the
Resize Pro Plugin is upsampling. Can it beat Qimage's Pyramid? One
classic measure of the amount of detail in a JPEG image is to look at
the file size: the bigger the file, the more detail. I cropped a
250x250–pixel area on one of my recent photos and enlarged it to 750x750
pixels using three methods: Photoshop's Bicubic Smoother, Qimage's
Pyramid interpolation, and the 20D Resize Pro Plugin. I saved these as
level 8 JPEGs from Photoshop with the sRGB ICC profile embedded.
File sizes
- Bicubic smoother: 137KB
- Qimage Pyramid: 142KB
- Resize Pro: 149KB
By that test, Resize Pro wins. But how do they look?
Example files
- Bicubic smoother
- Qimage Pyramid
- 20D Resize Pro Plugin
There's
more of something in the Resize Pro file. Is it better than Qimage?
Probably. Will it be worth the effort to do this extra step in Photoshop
for pictures I want to print rather than letting Qimage do it
automatically? Maybe.
That's why the real test, of course, is with
printed files. But there's a problem: I don't have any way to print
photos this large. My Canon i9100 can print at a maximum size of
13"x19". By resizing a 20D file by 300% (the amount used in this
"test"), I'm producing roughly a 24"x33" print at 300DPI. I would need
something like an Epson 7600, an HP Design Jet 130, or one of the new Canon large-format inkjet printers in order to test this out.
A3+
at 300DPI is about 166% enlargement for my 20D files. I'll probably do
some experiments soon but I don't expect to see as much of a difference
at this size between Qimage and Resize Pro.